life-echo/app-expo/src/features/voice/recorder.ts

import { Platform } from 'react-native';

import {
  AudioModule,
  type RecordingOptions,
  RecordingPresets,
} from 'expo-audio';
import { audioFocus } from '@/core/audio/audio-focus';

import type { RecorderStatus } from './types';

// Native module exposes AudioRecorder as constructor; ESLint import/namespace doesn't resolve it
// eslint-disable-next-line import/namespace -- AudioModule.AudioRecorder exists at runtime
const AudioRecorderCtor = AudioModule.AudioRecorder;

type StatusListener = (status: RecorderStatus) => void;
type RecordingCompleteListener = (uri: string, durationMs: number) => void;

/** Platform-specific recording options (expo-audio internal createRecordingOptions logic). */
function createRecordingOptions(
  options: RecordingOptions,
): Partial<RecordingOptions> {
  const common = {
    extension: options.extension,
    sampleRate: options.sampleRate,
    numberOfChannels: options.numberOfChannels,
    bitRate: options.bitRate,
    isMeteringEnabled: options.isMeteringEnabled ?? false,
  };
  if (Platform.OS === 'ios') return { ...common, ...options.ios };
  if (Platform.OS === 'android') return { ...common, ...options.android };
  return { ...common, ...options.web };
}

/**
 * Class-level wrapper over expo-audio recording.
 * No React dependency — hooks/ layer adapts this to React.
 */
interface RecorderInstance {
  prepareToRecordAsync(options?: Partial<RecordingOptions>): Promise<void>;
  record(): void;
  stop(): Promise<void>;
  uri: string | null;
}

export class VoiceRecorder {
  private recorder: RecorderInstance | null = null;
  private status: RecorderStatus = 'idle';
  private startTime = 0;
  private statusListeners = new Set<StatusListener>();
  private completeListeners = new Set<RecordingCompleteListener>();

  async requestPermission(): Promise<boolean> {
    const result = await AudioModule.requestRecordingPermissionsAsync();
    return result.granted;
  }

  async start(): Promise<boolean> {
    if (this.status !== 'idle') return false;

    const hasPermission = await this.requestPermission();
    if (!hasPermission) return false;

    const acquired = await audioFocus.acquireForRecording();
    if (!acquired) return false;

    this.setStatus('preparing');

    try {
      this.recorder = new AudioRecorderCtor(
        createRecordingOptions(RecordingPresets.HIGH_QUALITY),
      );
      await this.recorder.prepareToRecordAsync();
      this.recorder.record();
      this.startTime = Date.now();
      this.setStatus('recording');
      return true;
    } catch {
      await this.cleanup();
      return false;
    }
  }

  async stop(): Promise<{ uri: string; durationMs: number } | null> {
    if (!this.recorder || this.status !== 'recording') {
      return null;
    }

    this.setStatus('stopping');

    try {
      await this.recorder.stop();
      const uri = this.recorder.uri;
      const durationMs = Date.now() - this.startTime;

      if (uri) {
        for (const listener of this.completeListeners) {
          listener(uri, durationMs);
        }
      }

      await this.cleanup();
      return uri ? { uri, durationMs } : null;
    } catch {
      await this.cleanup();
      return null;
    }
  }

  async cancel(): Promise<void> {
    if (this.recorder) {
      try {
        await this.recorder.stop();
      } catch {
        // Already stopped or failed
      }
    }
    await this.cleanup();
  }

  getStatus(): RecorderStatus {
    return this.status;
  }

  getDurationMs(): number {
    if (this.status === 'recording' || this.status === 'paused') {
      return Date.now() - this.startTime;
    }
    return 0;
  }

  onStatusChange(listener: StatusListener): () => void {
    this.statusListeners.add(listener);
    return () => this.statusListeners.delete(listener);
  }

  onRecordingComplete(listener: RecordingCompleteListener): () => void {
    this.completeListeners.add(listener);
    return () => this.completeListeners.delete(listener);
  }

  private setStatus(next: RecorderStatus): void {
    if (this.status === next) return;
    this.status = next;
    for (const listener of this.statusListeners) {
      listener(next);
    }
  }

  private async cleanup(): Promise<void> {
    this.recorder = null;
    this.startTime = 0;
    this.setStatus('idle');
    await audioFocus.release();
  }
}